WASHINGTON — Ending a postelection detente, Senate leaders shredded each other Tuesday in increas­ingly bitter terms over a Democratic proposal to dramatically overhaul the chamber’s long-standing rules on filibusters.

The back-and-forth left the Senate in a partisan standoff that is ill suited for the bipartisan talks expected over the next four weeks to reach a compromise that would avert more than $500 billion in annual auto­matic tax hikes and spending cuts that are set to kick in after New Year’s Day.

The heated exchanges poisoned the bipartisan atmosphere that President Obama, House Speaker John A. ­Boehner, Republican of Ohio, and other congressional leaders had been trying to promote, hoping to settle nervous financial markets warily looking at Washington to see if a massive debt deal can be hatched to prevent a recession next year.

For a second straight day Senate majority leader Harry M. Reid, Democrat of Nevada, and minority leader Mitch ­McConnell, Republican of ­Kentucky, opened the chamber by engaging in a nearly hourlong feud over Reid’s emerging proposal to eliminate some filibusters. Reid accused the GOP leader of ‘‘abusing’’ the rules; McConnell accused the Democrat of ‘‘breaking the rules to change the rules.’’

Tuesday’s debate ended with McConnell repeating his warning that a Democratic rewrite of the chamber rules planned for early next year, if approved without any GOP votes, would prove toxic for compromise on the fiscal issues.

The Senate leaders are in a role reversal of where they stood in early 2005. The Democrats are now, as Republicans were then, led by a large bloc of junior senators demand­ing filibuster changes to speed up ­action in a chamber that has long boasted of being the ‘‘world’s greatest deliberative body.’’

Reid’s proposal, which he has sketched out only briefly in public, would eliminate the filibuster vote needed to formally begin debate on legislation. He would allow for a final filibuster vote, thus making the chamber run more efficiently. - WASHINGTON POST

WASHINGTON — A UN treaty promoting equal rights for the disabled faced an uncertain future in the Senate as ­Republicans objected Tuesday to taking up an international treaty during a lame-duck session of Congress and expressed concerns about ceding authority to the United Nations.

Supporters of the Convention on the Rights of Persons with Disabilities, which was signed by the George W. Bush administration in 2006, stressed that it was modeled after the 1990 Americans with Disabilities Act and required no changes in US law.

In September, 36 Republicans signed a letter opposing any action on international treaties during the post­election session. The opposition has more than enough votes to ­defeat the treaty, which needs a two-thirds majority to be ratified. The Senate voted 61-36 to move the treaty to the floor for debate.

The convention has been signed by 154 nations and ratified by 126 of those nations. President Obama signed it in 2009.

Senator John Kerry, Democrat of Massachusetts and chairman of the Senate Foreign Relations Committee, said the impact of the treaty ‘‘will echo around the world.’’ He said the Americans with Disabilities Act is the gold standard for protecting the rights of the disabled and the treaty would ‘‘take that gold standard and extend it to countries that have never heard of disability rights.’’ He said that it would benefit disabled American veterans who want to travel or work abroad.

The Leadership Conference on Civil and Human Rights, which represents more than 210 national organizations, said ratification ‘‘will reflect US commitment to disability rights and core American values such as the dignity of the individual, access to justice and the right to education.’’

But opponents — led by Senator Mike Lee, Republican of Utah — say that international treaties are by their nature a threat to American sovereign authority.

Lee also says treaty provisions referring to the ‘‘best interests of the child’’ could lead to the state, and not parents, deciding what is in a child’s best interest and that language stating that the disabled should have equal rights to reproductive health services could lead to abortions.

He said the treaty only states that a country’s laws permitting or banning health procedures should apply to the disabled as well. - ASSOCIATED PRESS

Obama hails agenda set by incoming Mexican leader

WASHINGTON — President Obama hailed an ‘‘ambitious reform agenda’’ set forth by the incoming president of Mexico as he and President-elect ­Enrique Pena Nieto met Tuesday at the White House.

Obama said it was fitting that the men were meeting even before Pena Nieto takes office on Saturday, calling it a sign of the close relationship between the two countries.

‘‘What happens in Mexico has an impact on our society,’’ Obama said before the Oval ­Office meeting, which also included Vice President Joe Biden and Secretary of State Hillary Rodham Clinton.

Obama said he had forged a close working relationship with Felipe Calderon, the outgoing Mexican president, and was confident he could establish a similar ‘‘close personal and professional relationship’’ with ­Pena Nieto.

Obama said he would press ahead with comprehensive immi­gration reform and looked forward to cooperation from Pena Nieto in longstanding US efforts to stem illegal immigration from Mexico.

Pena Nieto and said he was looking forward to strengthening already close relations between the countries. - ASSOCIATED PRESS

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